Environmental Pollution Effect Analysis of Lead Compounds in China Based on Life Cycle

Removal of Pb pollution using alginate-coupled magnetic sludge biochar: Solidification and stabilization behavior and electron promotion mechanisms

Environmental and human health problems caused by Pb pollution have attracted much attention, and solidification and stabilization are effective means for its remediation. Improving the ability of biochar to remediate heavy metals through modification is the focus of current biochar research. This study used calcium-alginate gel (GB) and Fe3+ (magnetic) to encapsulate and improve sludge biochar (SB), and explored the adsorption behavior and passivation mechanism of Pb2+ on it from outside to inside. The magnetic-biochar (MB) in magnetic-biochar-gel microspheres (MBGB) showed a homogeneous dispersion and part of the Fe ion was detached from the MB into the three-dimensional pores of the gel. The results of kinetic, isothermal and pH adsorption experiments showed that the MBGB has 108.4 % and 200 % higher Pb2+ adsorption capacity and rate than SB and can be applied to pH 3-9. The adsorption of Pb2+ by MBGB is a multilayer adsorption with both physical and chemical mechanisms. Mineralogical and electrochemical results demonstrate that the cross-linking of the gel with magnetic-biochar (MB) can provide a directional diffusion channel for Pb2+ from the outside to the inside. The electron transfer rate of MBGB was significantly higher than that of SB (222.2 %) after the reaction. The dissolved cations and electrons on the MB guide Pb2+ from the MBGB surface to the internal MB quickly via accelerating the electron transfer and migration rate between Pb2+ and MB. Subsequently, the abundance of PO43- on the MB ensures stable mineral precipitation (Pyromorphite). Moreover, four-step extraction analysis confirmed that most of Pb2+ in MBGB was stable (36.2 % acid-soluble and 47.6 % non-bioavailable). Meanwhile, the Pb adsorption efficiency of MBGB was still >93.0 % after three cycles of adsorption-desorption. Excellent reuse performance and stability guarantee the environmental security of MBGB. The results of the study provide theoretical support for the efficient treatment of Pb2+ polluted water assisted by gel materials.

Ni(II) and Pb(II) Removal Using Bacterial Cellulose Membranes

Bacterial cellulose (BC) is a highly crystalline nanosized material with a high number of active groups. This study focuses on the synthesis of BC membranes through fermentation, their characterization and application to remove Ni(II) and Pb(II) from wastewater by adsorption under different conditions. Four-day-grown BC membranes form three-dimensional nanofibril networks with a pH of 6.3 and a high cationic demand (52.5 μeq·g-1). The pseudo-second-order kinetic model and the Sips isotherm model best describe the adsorption of both metals. The intraparticle diffusion model of Ni(II) revealed a three-step mechanism of adsorption-plateau-adsorption, while Pb(II) adsorption followed a typical reducing-slope trend up to saturation. The highest removal of Ni(II) and Pb(II) was obtained at pH 4 with a BC dosage of 400 mg·L-1. The maximum adsorption capacities were 28.18 mg·g-1 and 8.49 mg·g-1 for Ni(II) and Pb(II), respectively, involving the total coverage of the material active sites. Thermodynamically, Ni(II) adsorption was exothermic, and Pb(II) was endothermic. The obtained values of sorption heat, activation and Gibbs' energy depicted a physisorption process. Ni(II) removal mechanism was ruled by crystallization on the metals adsorbed on the BC active groups, while Pb(II) was driven by the adsorption process, as shown by TEM images of the spent material.

The first ecological contamination study of avian mercury and lead in southeast Iran, Hamun International Wetlands

The concentrations of mercury (Hg) and lead (Pb) in feather samples of nine bird's species (n = 65) were determined from southeastern areas of Iran, Hamun International Wetlands. Hg concentrations were ranged from 0.40 to 3.00 mg/kg dry wt and from 0.38 to 1.76 mg/kg for primary and secondary feathers, respectively. Furthermore, Pb concentrations were ranged from 1.43 to 4.10 mg/kg and from 1.28 to 3.65 mg/kg for primary and secondary feathers, respectively. Deposition of metals varied significantly among the primary and secondary feathers of systematic category (families) for Hg and Pb (p < 0.001). It was found that there is a significant difference in feather Hg and Pb concentrations across species (p < 0.001) with highest concentrations in saker falcon (Falconidae) (Hg = 3.00 mg/kg and Pb = 4.10 mg/kg, primary feather) followed by little owl (Strigidae). Grey francolin (Phasianidae) contained the least amount of Hg (0.40 mg/kg) and Pb (1.43 mg/kg) in primary feather. The results showed that the highest concentrations of heavy metals were related to carnivores. Fish predators, omnivores, and insectivores were examined at the next level of metal concentration, with herbivores having the lowest concentrations of lead (1.43 mg/kg) and mercury (0.40 mg/kg). Birds with an open grasslands feeding strategy had the highest mercury and lead concentration. The average value for Pb was on the border of harmful effects (4 mg/kg). The results of this study indicate that mercury levels are lower than the threshold level for reproductive and behavioral harm (5 mg/kg).

Recent Progress on Fluorescent Probes in Heavy Metal Determinations for Food Safety: A Review

One of the main challenges faced in food safety is the accumulation of toxic heavy metals from environmental sources, which can sequentially endanger human health when they are consumed. It is invaluable to establish a practical assay for the determination of heavy metals for food safety. Among the current detection methods, technology based on fluorescent probes, with the advantages of sensitivity, convenience, accuracy, cost, and reliability, has recently shown pluralistic applications in the food industry, which is significant to ensure food safety. Hence, this review systematically presents the recent progress on novel fluorescent probes in determining heavy metals for food safety over the past five years, according to fluorophores and newly emerging sensing cores, which could contribute to broadening the prospects of fluorescent materials and establishing more practical assays for heavy metal determinations.

Lead pollution-related health of children in China: Disparity, challenge, and policy

Lead (Pb) is a neurotoxic metal, and no level of lead exposure is safe for children. China has still experienced problems on child lead poisoning even though the Chinese government has phased out leaded gasoline since 2000. The underlying problem affecting the lead pollution-related health of children in China remains to be comprehensively investigated. It is found that although the significant decline of BLLs, as the Geometric Mean (GM), from 91.40 μg/L^GM in 2001 to 37.52 μg/L^GM in 2018 is observed, the average BLLs of children are still above 50 μg/L or more [average 59.70 (60.50-65.02, 95 % CI) μg/L^GM] after phasing out leaded gasoline since 2000 in China. Lead exposure causes 29.67 MID per 1000 children with a loss of 98.23 (59.40-146.21, 95 % CI) DALYs per 1000 in China, which is greater than the levels reported from the Western Pacific Region and other low- and middle-income countries. A significant correlation is observed between the number of child crimes (NoCCs) and the outcomes of long-term lead exposure for children in China. Although the disparities in BLLs in China are strongly influenced by unequal distributions of potential multi-lead related sources (soil lead, PM2.5 lead, dust lead), unbalance development of local industrialization and economies, as well as incorrect health care for younger children, the notable emissions from coal combustion (CC) and non-ferrous metals (NMS) exploitation dominate the crucial sources of low-level lead exposure to children after phasing out leaded gasoline in China currently. Faced with the unequal and disparate distribution of BLLs in China, the big bottleneck is to decrease the BLLs exertions of 36-45 μg/L in the next few decades. The Chinese government needs to make more efforts on developing more strict guidelines, implementing more policy strategies on prevention and management of blood Pb poisoning, and monitoring the nationwide changes in children's BLLs continuously.

Detection Techniques for Lead Ions in Water: A Review

Lead pollution has increasingly become the focus of environmental pollution, which is a great harm to the ecological environment and human health. Strict control of the emission of lead pollutants and accurate monitoring of lead are very important. The lead ion detection technologies are introduced here, including spectrophotometry, electrochemical method, atomic absorption spectrometry, and other detection methods, and the methods' applicability, the advantages, and disadvantages are discussed. The detection limits of voltammetry and atomic absorption spectrometry are as low as 0.1 μg/L, and those of atomic absorption spectrometry are as low as 2 μg/L. The detection limit of photometry is higher (0.01 mg/L), but this method can be achieved in most laboratories. The application of different extraction pretreatment technologies in lead ion detection is introduced. The new technologies develop at home and abroad, such as precious metal nanogold technology, paper microfluidic technology, fluorescence molecular probe technology, spectroscopy, and other emerging technologies in recent years, are reviewed, and the principle and application of various technologies are expounded.

Potential Threat of Lead Oxide Nanoparticles for Food Crops: Comprehensive Understanding of the Impacts of Different Nanosized PbOx (x = 1, 2) on Maize (Zea mays L.) Seedlings In Vivo

PbO_x (PbO₂ and PbO, x = 1, 2) nanoparticles are emerging contaminants in dust, soil, and water due to extensive application of commercial lead products. As far as we know, the current studies are first conducted to understand the phytotoxic effects of PbO₂ (10 ± 3 nm) and PbO NPs (20 ± 5 nm) on maize (Zea mays L.) grown in hydroponic treatments. The exposure assays indicated that phytotoxic effects were dose- and size-dependent on PbO_x NPs. Water uptake would be the crucial mechanism to govern the effects of PbO_x on maize seed germination and root elongation, while the nanosize of particles and water transpiration processes would control maize growth and biomass production. PbO_x NPs significantly influenced the macro- and micronutrients in roots and shoots of maize and significantly affected the maize growth and grain development. Our findings provide clear-cut evidence that PbO/PbO₂ NPs can bioaccumulate in maize cell organelles via apoplastic and symplastic routes from the seed and root pathways along with water uptake and transportation. The significance of this research elucidates the impacts of PbO/PbO₂ NPs on food security and indicates the threat of emerging PbO/PbO₂ NPs to human dietary health.

NLRP3 activation in microglia contributes to learning and memory impairment induced by chronic lead exposure in mice

Lead (Pb)-induced microglial activation and neuroinflammation has been considered as one of the main pathological events of Pb neurotoxicity. The NLRP3 inflammasome signaling pathway is a major contributor to the neuroinflammatory process in the central nervous system. However, the relationship between chronic Pb exposure and neurogenic NLRP3 inflammasome is unclear. Therefore, the aim of this study was to characterize the role of NLRP3 inflammasome activation during the chronic Pb exposure using in vitro and in vivo models. Our results showed that chronic Pb exposure induce learning and memory impairment in mice, mainly related to the activation of microglia and NLRP3 inflammasome. This phenomenon was reversed in mice by treating with the NLRP3 inhibitor MCC950 and using NLRP3-/- mice. In addition, Pb caused the activation of NLRP3 inflammasome, the production of mitochondrial ROS (mtROS), and mitochondrial Ca2+ overload in BV2 cells. Amelioration of mtROS abolished Pb-induced NLRP3 inflammasome activation. Moreover, after regulation of Ca2+ redistribution, mtROS and NLRP3 inflammasome activation was restored. In conclusion, NLRP3 inflammasome activation in microglia plays a vital role in Pb neurotoxicity, by a novel mechanism of enhancing mtROS production and Ca2+ redistribution.

Glycine protects the male reproductive system against lead toxicity via alleviating oxidative stress, preventing sperm mitochondrial impairment, improving kinematics of sperm, and blunting the downregulation of enzymes involved in the steroidogenesis

Lead (Pb) is a highly toxic heavy metal widely dispersed in the environment because of human industrial activities. Many studies revealed that Pb could adversely affect several organs, including the male reproductive system. Pb-induced reproductive toxicity could lead to infertility. Thus, finding safe and clinically applicable protective agents against this complication is important. It has been found that oxidative stress plays a fundamental role in the pathogenesis of Pb-induced reprotoxicity. Glycine is the simplest amino acid with a wide range of pharmacological activities. It has been found that glycine could attenuate oxidative stress and mitochondrial impairment in various experimental models. The current study was designed to evaluate the role of glycine in Pb-induced reproductive toxicity in male mice. Male BALB/c mice received Pb (20 mg/kg/day; gavage; 35 consecutive days) and treated with glycine (250 and 500 mg/kg/day; gavage; 35 consecutive days). Then, reproductive system weight indices, biomarkers of oxidative stress in the testis and isolated sperm, sperm kinetic, sperm mitochondrial indices, and testis histopathological alterations were monitored. A significant change in testis, epididymis, and Vas deferens weight was evident in Pb-treated animals. Markers of oxidative stress were also significantly increased in the testis and isolated sperm of the Pb-treated group. A significant disruption in sperm kinetic was also evident when mice received Pb. Moreover, Pb exposure caused significant deterioration in sperm mitochondrial indices. Tubular injury, tubular desquamation, and decreased spermatogenic index were histopathological alterations detected in Pb-treated mice. It was found that glycine significantly blunted oxidative stress markers in testis and sperm, improved sperm mitochondrial parameters, causing considerable higher velocity-related indices (VSL, VCL, and VAP) and percentages of progressively motile sperm, and decreased testis histopathological changes in Pb-exposed animals. These data suggest glycine as a potential protective agent against Pb-induced reproductive toxicity. The effects of glycine on oxidative stress markers and mitochondrial function play a key role in its protective mechanism.

Adsorption Study of Continuous Heavy Metal Ions (Pb2+, Cd2+, Ni2+) Removal Using Cocoa (Theobroma cacao L.) Pod Husks

The serious toxicological effects of heavy metal ions in aquatic ecosystems have motivated the search for alternatives to reduce contamination of water sources from industrial wastewater. In this work, continuous adsorption of nickel, cadmium, and lead was assessed using a packed bed column filled with Cocoa (Theobroma cacao L.) pod husks widely available in the northern region of Colombia. The physicochemical characterization of the agricultural biomass was performed to quantify its chemical composition by bromatological, FT-IR, and energy-dispersive X-ray spectroscopy (EDS). The breakthrough curves were constructed for all heavy metal ions with bed depth of 4 and 7.5 cm, taking aliquots at 10, 30, 60, 90, 120, 150, 180, 210, 240, and 270 min. Moreover, experimental data were fitted to adsorption models in continuous mode to predict adsorptive performance (Adams−Bohart, Thomas, and Yoon−Nelson). For the FT-IR analysis of biomass before and after adsorption, the most representative bands occur around 3200−3900 cm−1 attributed to the presence of hydroxyl groups, showing the destruction of the peaks of lignocellulosic materials. The breakthrough curves revealed that for a 7.5 cm bed, adsorption performance reported the following order of promising results: Pb2+ > Ni2+ > Cd2+; while for a 4 cm bed, Pb2+ > Ni2+. The mechanism of adsorption of the evaluated metals onto cocoa pod husk was attributed to cationic exchange and microprecipitation due to the presence of Ca, K, and Si in the structure of the bio-adsorbent. Finally, the continuous adsorption was modeled under the mathematical expressions of Adams−Bohart, Thomas, and Yoon−Nelson reporting good fitting with correlation coefficient above 0.95.

Noval porous phosphate-solubilizing bacteria beads loaded with BC/nZVI enhanced the transformation of lead fractions and its microecological regulation mechanism in soil

Soil lead pollution becomes a serious environmental problem. Microbial remediation has received widespread attentions due to high efficiency and no secondary pollution. In this research, a noval porous spherical phosphate-solubilizing bacteria bead loaded with biochar/nZVI (Bio-bead) was used to passivate lead in soil, and the effects and microecological regulation mechanisms of this process were also investigated. The results showed that the pH, OM, and AP of soil in the Bio-bead group were increased and the ORP was decreased over time compared with the blank group. The proportion of stable (oxidizable and residue) fractions of lead in Bio-bead group (45%) was much higher than that of the blank group (35%). In addition, the result of microbial community structure showed that Bio-beads did not change the species of dominant bacterial, excepting the abundance of Pseudomonas increased significantly and the abundance of Sphingomonas reduced during remediation. Redundancy analysis showed that pH, OM, AP and the ratio of residual and oxidizable fractions lead in soil were positively correlated with the abundance of Pseudomonas, while ORP was negatively correlated with the abundance of Pseudomonas. These findings have proved that Bio-bead is a potential strategy for remediation of lead-contaminated soil even in complexed soils.

New insights into the pollutant composition of stormwater treating wetlands

With intensified climate change and urbanisation, constructed wetland (CW) serves as an alternative to conventional wastewater treatment plants. In Australia, the primary function of CW is to reduce sediments, nutrients from runoffs and attenuate floods. However, water quality analysis after construction is limited, hence, pollutant composition in established CWs and target pollutants in many guidelines remain outdated. To refresh the understanding of pollutants in urban discharges, this study reviewed two CWs in industrialised regions of Victoria, Australia. A total number of 26 pollutants were analysed in the collected water and sediment samples from both CW. The findings highlighted excessive concentrations of Zinc, Aluminium, Iron and Copper in one wetland and less commonly found pollutants like Barium, Titanium and Strontium are also detected. While Arsenic, Zinc, Copper, Nickel and hydrocarbons' accumulations are particularly significant in the other wetland. This study also reviews the pollutants discovered in 136 stormwater wetlands and covers the sources and impacts of various metal pollutants in stormwater runoffs. Overall, it is found that the concentrations of Zinc, Aluminium and Iron are particularly high in the CWs reviewed. This study brings attention to the pollutants profile of established CWs and the impact of heavy metals on the aquatic environment. The findings from this research revealed that the existing design and management guidelines for constructed wetlands in urban catchments are lacking in reduction targets for metal pollutants, thus improvements are essential to safeguard the water quality and performance of CWs.

BiFeO3-Based Relaxor Ferroelectrics for Energy Storage: Progress and Prospects

Dielectric capacitors have been widely studied because their electrostatic storage capacity is enormous, and they can deliver the stored energy in a very short time. Relaxor ferroelectrics-based dielectric capacitors have gained tremendous importance for the efficient storage of electrical energy. Relaxor ferroelectrics possess low dielectric loss, low remanent polarization, high saturation polarization, and high breakdown strength, which are the main parameters for energy storage. This article focuses on a timely review of the energy storage performance of BiFeO3-based relaxor ferroelectrics in bulk ceramics, multilayers, and thin film forms. The article begins with a general introduction to various energy storage systems and the need for dielectric capacitors as energy storage devices. This is followed by a brief discussion on the mechanism of energy storage in capacitors, ferroelectrics, anti-ferroelectrics, and relaxor ferroelectrics as potential candidates for energy storage. The remainder of this article is devoted to reviewing the energy storage performance of bulk ceramics, multilayers, and thin films of BiFeO3-based relaxor ferroelectrics, along with a discussion of strategies to address some of the issues associated with their application as energy storage systems.

Multi-isotope signatures (Cu, Zn, Pb) of different particle sizes in road-deposited sediments: a case study from industrial area

Road-deposited sediments (RDS) are major sources of heavy metal contamination in urban areas and adversely affect surrounding environments and human health. Multi-isotope combinations (Cu, Zn, and Pb), which serve as environmental tracers, enable the identification and management of metal contaminants in RDS. Here, we present Cu, Zn, and Pb isotopic data for the first time in size-fractionated RDS samples collected from industrial areas to describe the relationship between the RDS and total suspended solids (TSS) in runoff, and to explore the feasibility of using multi-isotopes to identify sources of metal contamination. RDS in the industrial study areas had high concentrations of Cu, Zn, and Pb, and their δ65CuAE647, δ66ZnIRMM3702, and 206Pb/207Pb values ranged from − 0.33 to + 0.73‰, − 0.36 to + 0.01‰, and 1.1418 to 1.1616, respectively. The variation in δ65CuAE647 (δ65Cumax-min) was larger than that of δ66ZnIRMM3702 (i.e., δ66Znmax-min), and the isotope values of Zn and Pb (206Pb/207Pb) tended to increase with the concentrations of these elements. Meanwhile, the fine RDS particles (< 63 µm) had similar Cu, Zn, and Pb isotopic compositions to those of TSS. Hierarchical cluster analyses revealed that the < 63 µm RDS fractions were associated with the TSS. Our results also showed that a combination of Pb and either Cu or Zn could be used to distinguish between RDS and non-exhaust emissions (e.g., brake pads, tires, etc.). Multi-isotope approaches utilizing Cu, Zn, and Pb and more robust isotopic data on individual sources of metal contamination could be useful for identifying pollution sources and understanding their environmental impacts.

Advances in the Functional Nucleic Acid Biosensors for Detection of Lead Ions

Lead ions (Pb²⁺) are destructive to the natural environment and public health, so the efficient detection of Pb²⁺ is particularly important. Although the instrumental analysis methods have high accuracy, they require high cost and precise operation, which limits their wide application. Therefore, many strategies have been extensively studied for detecting Pb²⁺ by biosensors. Functional nucleic acids have become an efficient tool in this field. This review focuses on the recent biosensors of detecting Pb²⁺ based on functional nucleic acids from 2010 to 2020, in which DNAzyme, DNA G-quadruplex and aptamer will be introduced. The biosensors are divided into three categories that colorimetric, fluorometric and electrochemical biosensors according to the different reported signals. The action mechanism and detection effect of each biosensor are explained. Finally, the present situation of nucleic acid biosensor for the detection of Pb²⁺ is summarized and the future research direction is prospected.

Effects of long-term high-level lead exposure on the immune function of workers

This work was undertaken to study the immunomodulatory effects of long-term exposure to varying levels of lead (Pb) in workers. A total of 49 people who underwent occupational health examinations from 2009 to 2018 were selected as study subjects. Differences between the two group populations regarding the levels of T-lymphocytes, B-lymphocytes, natural killer (NK) cells, and granulocytes, as well as the levels of T_H1/T_H2/T_H17 cytokines, were evaluated. The results indicated that the percentages of CD3⁺ cells in the high-Pb group were significantly higher than those in the low-Pb counterparts (p < .05). In contrast, the percentages of CD3^-CD16⁺CD56⁺ cells were significantly lower in the high-Pb workers. There were no significant differences in other immunommy cells and T_H1/T_H2/T_H17 cytokine between the groups. CD3⁺ cell levels in workers positively correlated with blood Pb levels (Rs = 0.378, p = .007), while the expression of CD3^-CD16⁺CD56⁺ cells was negatively correlated (Rs = -0.320, p = .025). There was no significant correlation between blood Pb concentration and the other immune endpoints evaluated here.

Lead Emissions and Population Vulnerability in the Detroit Metropolitan Area, 2006-2013: Impact of Pollution, Housing Age and Neighborhood Racial Isolation and Poverty on Blood Lead in Children

This research investigates the relationships between airborne and depositional industrial lead emission concentrations modeled using Environmental Protection Agency’s (EPA’s) American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) and childhood blood lead levels (BLL) in the Detroit Metropolitan Area (DMA) 2006–2013. Linear and mediation interaction regression models estimated the effects of older housing and airborne and depositional lead emission concentrations on black and white childhood BLLs, controlling for neighborhood levels of racial isolation and poverty—important social structures in the DMA. The results showed a direct relationship between airborne and depositional lead emissions and higher childhood BLL, after controlling for median housing age. Lead emissions also exacerbated the effect of older housing on black and white children’s BLLs (indirect relationship), after controlling for social structures. Findings from this research indicate that black and white children exposed to lead-based paint/pipes in older housing are further impacted by industrial lead pollution that may lead to permanent neurological damage.